Methyl violet ink toners and carbon inks



Patented Jan. 8, 1946 METHYL vrom'r no: Tom-ms cannon mus AND Werner F.Goepfert, Oradeil, N. 3., assignor to. Interchemical Corporation, NewYork, N. E, a

corporation of Ohio No Drawing. Application May is, 1942,

Serial No. 443,130

' a Claims. (or. inc-23 This invention relates to toners for carbon inksand to inks containing the same.

In the preparation of carbon lnks,'it is customary to add a dark coloredtoner to give the ink the desired shade or tone. The most common'tonersfor this purpose are made from dye bases which are of deep blue topurple color, such as Victoria blue and methyl violet. These basic dyebases must be combined with an acid radical to develop the full colorstrength of the dye. If acid radicals of higher fatty acids areemployed, the resulting dyes become .cil soluble. For this purpose oleicacid has been used. However, the use of oleic acid has not been entirelysatisfactory because the dye reaction product, or toner. shows anexcessive amount of creeping and penetration tration, wetting andprinting qualities to the toners. y I

The preparation and use of these toners are illustrated in the followingexamples:

Example 1.--Myristic acid toner 91.2 parts by weight of myristic acidwere heated'to about 85 C., and 50 parts by weight of methyl violet basewere added slowly with agitation. Upon complete addition of the dyebase, the temperature was raised to 100 0., and maintained for fifteenminutes, after which the mateinto' the paper. This usually becomesapparent as a discoloration or halo around the spot where the ink hasbeen deposited by transfer from the carbon paper. Also, the strength ofthe ink is reduced by the creeping of the dye through the carbon paperbacking, thus shortening the life or usefulness of the carbon paper.

- Stearic acid has been suggested as a substitute for the oleic acid as'a solubilizing agent for methyl violet, but stearic acid toners are toocrystalline in nature so that inks containing them show a bloom onprinting which is easily rubbed ofi. In addition the stearic acidmodified methyl violet toner does not have the capacity to "wet 'carbonblack sufiiciently to makeits use practical.

This invention provides toners which are equal to or greater than theoleic acid treated dye bases in coloring strength, and which arecharacterized' by their relative lack of creeping and at the same timedo not cause a bloom on printing which can be rubbed off. Also,thetoners show marked wettin of carbon black when I milled in the usualwaxes employed in making. transfer inks. The invention also contemplatescarbon inks containing the new toners.

The toners of this invention are made by combining methyl violet basewith a fatty acid, or

mixture of acids, selected from the group con- 1 sisting of myristic andpalmitic acids;- It is believed that the dye base and acid forma-compound of the type of an amine salt.

The myristic and palmitic acid reaction prod-' ucts, or toners, areunique in that they combine the characteristics of non-penetration intoporous material on which the ink isplaced and yet do not form a bloom onprinted surfaces. of these two fatty acids myristic is preferred becauseit imparts the best 'balance of non-penerial was allowed to cool. Thetoner form'ed had a bronze-purple color, and possessed a relatively 15high viscosity. A more wax-like material may be obtained by using a'greater proportion of myristic acid.

E'xizmpte 2.Palmitic acid toners as Another toner was preparedby'employing palmitic acid in place of the myristic acid of Example 1.This toner was slightlymore solid than the myristic acid toner, being amedium hard material which sheared very easily with aknife.

Example 3 Several carbon inks were prepared with the toners of Examples1 and 2 by heating and grinding the following materials together:

Parts by weight Carnauba wax 15 to 25 Mixture of carbon black andlogwood black 25 to 85 Mineral oil 25 to 35 Toner of Example 1 or 2 1.5to 4 Victoria blue dye 1.5 to 5 The Victoria blue dye was in the form ofthe E01 salt.

Other vegetable waxes be substituted for part of the camauba wax, suchas candelilla wax. Also, the toners of this invention permit the uniformdispersion of carbon black in other waxy media, such as pentaerythritoldibehenate and stearyi alcohol, whichordin'arliy floccuiate carbon blackwhen other tonersare used.,

- It is obviously not necessary thatthe acid medium with which the dyebase is combined be pure myrlstic or palmitic acid, or a mixturethereof, but it should not contain very large amounts of other acids.Satisfactory carbon ink toners have been made according to thisinvention where the acid medium contained as much as about 20% of otherfatty acids, but the amount of impurities should preferably be" lessthan this.

Similar-mother dye bases may be added'tothetonersorthisinventlonortotheinkscontainingthe tonersibobtainparticular shades or hues. However, the benefits or this not berealized in the formulation of carbon inks unless the methyl violettoners herein described constitute an appreciable part of the coloringmaterials used to tone the ink.

The employment oi toners of this invention in certain kinds oiprintinginks forms the subjectmatter of copending application Serial No.

443,128, flied May 15, 1942.

I claim:

invention willor halo about impressions made therefrom on paper, and theexcellent dispersion of the carbon black in the composition.

3. A carbon ink comprising a wax vehicle, colored with a majorproportion of carbon black, and a minor proportion of an oil-solubletoner, which is the: reaction product or methyl violet and myristicacid, the ink being characterexcellent dispersion or the carbon blackinthe composition.

1: The reaction product of approximately nine parts by weightot'myristic acid and five parts by weight ofmethyl violet base, theproduct being an oil-soluble bronze-purple liquid 01' high viscositywhich hasa high dispersive action on carbon black in waxy and oilymedia. I

2. A carbon ink comprising a wax vehicle, colored with a majorproportionof carbon black, and a minor proportion 01' an oil-solubletoner, which is the reaction product 01' methyl violet base, and atleast one fatty acid of the group consisting of myristic and palmiticacids, the ink being characterized by its lack oi bloom, the lack v4. Acarbon ink comprising'a wax vehicle in which carbon black tends tofloccuiate, colored with a major proportion 01 carbon black, andv aminor proportion oi. an oil-soluble toner which is the reaction productof live parts by weight of methyl violet base, and nine parts by weightof at least one fatty acid 01 the group consisting of myristic andpalmitic acids, the ink being characterized by its lack of bloom, thelack of halo about impressions made therefrom on papenand the excellentdispersion of the carbon black in the composition.

WERNER. F. GOEPFERT.

